Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
  • A61M5/178—Syringes
  • A61M5/28—Syringe ampoules or carpules, i.e. ampoules or carpules provided with a needle
  • A61M5/281—Syringe ampoules or carpules, i.e. ampoules or carpules provided with a needle using emptying means to expel or eject media, e.g. pistons, deformation of the ampoule, or telescoping of the ampoule
  • A61M5/283—Syringe ampoules or carpules, i.e. ampoules or carpules provided with a needle using emptying means to expel or eject media, e.g. pistons, deformation of the ampoule, or telescoping of the ampoule by telescoping of ampoules or carpules with the syringe body
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
  • A61M5/178—Syringes
  • A61M5/31—Details
  • A61M5/32—Needles; Details of needles pertaining to their connection with syringe or hub; Accessories for bringing the needle into, or holding the needle on, the body; Devices for protection of needles
  • A61M5/3202—Devices for protection of the needle before use, e.g. caps

Definitions

• This invention concerns syringes and more particularly, but not exclusively, medical syringes.
• Modern medical syringes offer a variety of benefits such as disposability, sterility, economy, wide availability, etc. , but they can be regarded as inappropriate relative to a commonly occurring situation, namely, one requiring the administration of a drug in a standardised amount.
• the inappropriateness arises from the fact that the syringe body and its needle are usually separately wrapped and so must be unwrapped, suitably connected, and then filled, prior to use.
• the frequency of the situation in question is recognised insofar as most drugs are now available in standarised single dosage ampoules for syringe filling, but it is evident that a wastage is entailed in syringe/ampoule materials and also in the time of skilled drug-administration personnel.
• a syringe comprising: a barrel in the form of a tube closed at one end; a piston sealably and longitudinally slidably located in said barrel, said piston being formed in part as a membrane extending transversely across the interior of said barrel; a plunger located for longitudinal sliding movement into, said barrel to engage and urge said piston thereinto; and a needle projecting through said plunger into and out of said barrel.
• material to be dispensed is pre-charged into the space defined between the closed end of the barrel and the piston, and movement of the plunger into the barrel first causes the needle to pierce the piston membrane to communicate with the material and thereafter the plunger urges the piston into the barrel to expel material through the needle.
• a protective cap is located over the needle and other parts projecting from the barrel.
• This cap provides mechanical protection and can, when required, also ensure sterility prior to use.
• Another preferred feature of the proposed syringe comprises adaptation of the mutually facing surfaces of the piston and plunger/needle assembly to allow or to cause interlocking engagement therebetween. Such engagement enables the piston to be subjected to withdrawal as well as inward movement by the plunger. This is particularly appropriate for intravenous injections, when it is necessary to check that the needle is in a vein prior to injecting the contents of the barrel. Partial withdrawal of the plunger, with piston attached, will cause blood to be drawn into the barrel signifying the correct location of the needle.
• Figures 2 and 3 similarly illustrate, in part, respectively different modified forms of the embodiment of Figure 1.
• the syringe embodiment of Figure 1 is intended for medical use and comprises a barrel 10, a piston 20, a plunger 30, a needle 4 ⁇ , and a cap 50.
• the barrel 10 is of hollow substantially circular cylindrical form with a side wall 11 and one end wall 12, the other end being open.
• the side wall 11 is formed with a radially outwardly projecting flange 13 ' adjacent the open end of the barrel.
• the piston 20 comprises a main body part 21 of generally hollow cylindrical form with its outer surface shaped to define three, say, circumferential ribs 22 successively longitudinally spaced therealong and of such diameter as to allow slidable sealing location of the piston in the barrel.
• the end of the piston body part 21 nearer to the open end of the barrel is closed by a membrane 23.
• the plunger 0 also comprises a main body part 31 of generally cylindrical form and of such a diameter as to allow slidable location in the barrel.
• the part 31 s of stepped form, with a portion 3 of larger diameter slidably located in the barrel, and a portion 33 of lesser diameter, the latter portion being located, prior to use, beyond the barrel as shown.
• the portion 32 is preferably fluted, or has polygonal or other circumferentially indented cross-sectional shape rather than one which seals in the barrel, and the portion 33 is formed with a radially outwardly projecting flange 3 adjacent its end further from the barrel.
• the part 31 is coaxially extended from its portion J, > by an elongate portion 35 of further reduced diameter and which terminates at its free end in a divergently conical or other transversely enlarged portion 36, this last portion also being of lesser diameter than the part 31.
• the needle 4 ⁇ is longitudinally bored, chamfered at each end, longer than the plunger 30, and secured coaxially in the pl nger to project from both ends thereof.
• the cap 50* comprises a shell 51 of circular cylindrical form extending at one end into a closure which may be tapered as shown, with the other end being open.
• the shell may be formed as shown to the same diameter at its open end as the barrel to abut therewith, with the open end of the shell being continued into an expanded rim 52 having* an internal groove 53 to seat over the barrel flange 13 in a snap fit.
• the barrel is suitably moulded from glass or plastics material, such as polystyrene or polypropylene, which is compatible with drugs containment, and the barrel will normally be non-opaque.
• the piston is suitably moulded from rubber or other elastomeric material to facilitate the desired sliding and sealing in the barrel, this being enhanced by the ribs 22.
• the piston material also is to be compatible with drugs containment.
• the plunger and cap are also suitably moulded from plastics material, which may be common to the barrel, although neither need be non-opaque.
• the needle will normally be of metal and this may be secured in the plunger by moulding of the latter around the former, or by cementing or other appropriate technique.
• a drug is contained in the space defined between the closed end portions of the barrel and the piston.
• the syringe is prepared for use simply by removing the cap, and then urging the plunger into the barrel so that the needle pierces the piston membrane, whereafter continuation of this plunger movement engages the plunger with the piston to urge the latter into the barrel and thereby to eject the drug by way of the needle.
• the snap fit connection of the cap on the barrel can provide a mechanical seal which maintains sterility by preventing air flow to and from the interior of the device, and this connection can be made secure by heat sealing at one or more points therearound with separation being initiated by rotation of the cap to break the heat sealed joints.
• Sterility of the capped syringe interior and its drugs content can alternatively, or additionally, be ensured by taping around the barrel-cap connection, and such a measure is beneficial in providing a visual indication that the seal has not been broken prior to use.
• the plunger portion 33 & nd its flange 34 afford an easy grip when applying the needle to a patient before plunger action.
• the plunger portions 35 and 36 can serve this same function and additionally serve to facilitate plunger actuation.
• This last function suitably involves location of two fingers around portion 35 to press on portion 33 in association with thumb-engagement of the barrel end wall 12 to urge the plunger into the barrel. The operator will know when the prescribed volume of drug has been administered as the plunger pushes the piston to the end wall 12 to limit movement, and in addition the drug containing space between the barrel end and piston can be seen to be emptied.
• the fluted or polygonal shape of the plunger body part 31 tracks the plunger in the barrel with a minimal engagement to afford low friction, while affording passageways for air movement to and from the adjoining space in the barrel. This feature also represents an economy in reducing the material content of the plunger.
• the piston or at least its membrane, must be of such a nature as to seal around the needle when pierced thereby.
• the membrane preferably self-seals after withdrawal, for location of a needle through the membrane can be used to allow egress of air from the barrel when the piston is first inserted.
• such a needle can be used to introduce the drug into the barrel through the membrane and at the same time to force the piston along the barrel, whereafter the plunger and cap can be assembled with the barrel.
• the syringe just described can be pre-charged with a drug in an appropriate volume such that use with plunger movement within the barrel forces the piston to the end of the barrel causing delivery of a predetermined volumetric dose.
• the outer end of the needle is suitably inserted into the patient while gripping the appropriate portion of the plunger, but without urging the plunger into the barrel.
• appropriate needle location is indicated by flash back of blood into the space between the plunger and piston.
• the plunger is preferably modified compared to that described above so that the portion 32 provides only capillary sized passageways between itself and the barrel to prevent spillage of blood during subsequent plunger actuation.
• the syringe can be pre-sterilised prior to assembly, or after assembly, by gamma radiation.
• the drug can be inserted through a needle as described above under sterile conditions at a later stage, or also be sterilised in situ by gamma radiation.
• the needle, plunger and space between the plunger and piston can be sterilised by ethylene oxide diffusing through the gap between the engaged cap and barrel, or by gamma radiation. The syringe then requires no preparation other than removal of the cap 50.
• the mutually facing surfaces of the piston 20 and plunger 0 are adapted to allow interlocking engagement therebetween.
• the relevant inner end of the plunger includes a coaxial portion 37 of reduced diameter extending around and partway along the associated projecting end of the needle 40.
• This plunger portion 37 s formed with an external thread 38 complementary with an internal thread 24 formed within the nearer end of the hollow of piston 20.
• the membrane 23 is suitably relocated within the piston, or at the further end thereof, to allow inter-engagement of the threads 24 and 38.
• the piston can additionally be subjected to withdrawal movement by way of the plunger. Also, the inter-engagement of the plunger with the piston assists in more positively locating the former in the barrel. This is particularly beneficial in the case where the plunger is fluted, polygonal or of other such shaping.
• the plunger can be heat sealed with the barrel at one or more points around their adjacent circumferences, as proposed above for the barrel and cap, with movement being initiated when required by a snap action.
• the rotation movement necessary to plunger-piston inter-engagement can be prevented by the provision of internal projections within the cap to locate in the concavities of the plunger when fluted or similarly shaped.
• the cap should be prevented from rotation by an appropriate one of the security measures discussed earlier above-
• the syringe barrel can be provided with scale markings to allow for dispensing of only part of its drug content. Equally such markings can be employed for the purpose of multiple dispensing. In thi-s last case it may be appropriate to allow for needle replacement and this can be accommodated by modification of the illustrated syringe to terminate the outer end of the needle, possibly within plunger portion 36. in a luer or other fitting for connection to conventional needles or other components.
• Figure 3 shows one such modification in which the barrel end wall 12 is opened for co-operation with a rubber or other elastomeric plug 60 for closure of the wall after dried-drug charging of the barrel, possibly by way of the cavity 6l defined by the interior part of
• the plug 60 incorporates a membrane 62 to function in self-sealing manner relative to a needle, such as that of a syringe as illustrated in Figure 1, whereby a prescribed volume of solvent is applied to the drug to dissolve it, at the same time pushing the piston down the barrel.
• the plug is preferably housed behind an outer cover 63 connected to the end of the barrel, this cover having a central aperture to allow access of a needle and diluent to the plug membrane 62.

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Citations (8)

• 1980
  • 1980-12-12 JP JP50016180A patent/JPS56501669A/ja active Pending
  • 1980-12-12 EP EP19800902394 patent/EP0047744A1/en not_active Withdrawn
  • 1980-12-12 WO PCT/GB1980/000215 patent/WO1981001657A1/en unknown

Patent Citations (8)

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